Drying kiln



Feb. 21, 1956 H. GEUL 2,735,192

DRYING KILN Filed March 25, 1955 5 Sheets-Sheet l I llIll/ll//lllllllllfr/l/l WWW OKNFyS H. GEUL.

DRYING KILN Feb. 2l, 1956 3 Sheets-Sheet 2 Filed March 23, 1953 H. GEUL DRYING KILN Feb. 2l, 1956 3 Sheets-Sheet 3 Filed March 25, 1953 United States PatentO DRYING KILN Hermann Geul, Stuttgart-Hedellingen, Germany Application March 23, 1953, Serial No. 344,110 Claims priority, application Germany October 3, 1952 3 Claims. (Cl. 34-223) This invention relates to a kiln. In particular, the invention is directed to the drying of piles of material separated into horizontal layers by spacers.

Ordinarily in kilns, stacks of lumber or other material are dried by air or steam forced by blowers around and between the layers of material.` The drying system conventionally included a rather elaborate housing for the system of conduits and blowers'and wasted a good part of the drying energy, in spite of the expensive plant construction.

The object of the instant invention is to construct a kiln of simple, etlicient structure, which makes maximum use of the drying medium.

ln general, this and other objects of the invention are accomplished by stacking the material to be dried in horizontal layers separated by spacers, and constructing a kiln which closely iits the stacked material with just suflicient wall space being provided to house a fan, heating elements, and curved baffle walls. The fan is of a size such that air is pulled by suction through one-half of the piled material, deflected by curved walls and blown under pressure through the other half of the piled material, and then again deiiected by curved walls into the suction area. One or more fans can be used to circulate the drying medium.

The means by which the objects of the invention are obtained are described more fully with reference to the accompanying drawings, in which:

Figure l is a cross-sectional view through a kiln constructed according to the invention;

Figure 2 is a cross-sectional view of a rst modified form of kiln;

Figure 3 is a cross-sectional view of a second modiiied form of kiln;

Figure 4 is a cross-sectional view of a third modified form of kiln;

Figure 5 is a horizontal cross-sectional view of a fourth form of kiln; and

Figure 6 is a vertical cross-sectional view of the kiln shown in Figure 5.

As shown in Figure l, the kiln 1 encloses a chamber in the bottom of which are tracks upon which a carriage 3 can be run. The kiln is designed so that the ceiling 4 barely clears material carried by the carriage, and the lower side walls are as close as possible to the carriage from the ground to points 5 which are equal to the height of the carriage. This carriage supports a pile of lumber, or other material 6, the horizontal layers being separated by spacers 7 so that air may circulate between the layers.

A fan 8 is mounted on one side wall halfway of the height of the pile of material. This fan has a diameter equal to one-half the major dimension of the pile of lumber. In this figure the height of the pile is greater than its horizontal length, so that the fan covers one-half the height of the pile. Heating pipes 9 are mounted above and below the fan.

The inner side walls of the chamber are curved to provide for the circulation of the air by fan 8. The walls ICC are curved so that an apex 12 is formed on the line of theY axis of the fan, and thusthere appears an upper curved section 13 and a lower curved section 14 on the side wall ing gas passing through the upper twoquarters, whiler curved wall 14 likewise serves the lowertwo quarters. Half of the pile is subject to suction flow of the drying gas, while the other half of the pile is in a pressure zone.

As shown by the arrows, the fan' 8 acts as a suction fan to draw air through the centerv two quarters of the pile of lumber, and thisl air is directed by the curved wall to be circulated-under pressure through the heating pipes 9 and through the top and bottom quarters of the pile of lumber. The air, after passing through the pile, strikes curved walls 13 and 14, respectively, to be thus directed toward the middle two quarters of the pile, where it is drawn by suction through the pile. Due to the closeness of the fitting of the walls, all the heating air is conned to the pile and is eciently employed to dry the lumber. The air is constantly recirculated, and conventional valves may be employed to permit the escape of air saturated with moisture drawn from the lumber.

In Figure 2 the structure is modified by employing a blower fan 8 on the opposite side of the chamber from fan 8. The circulation of the drying medium is as described for Figure l, additional rapidity of circulation being obtained by the second blower.

In Figure 3 the structure is modified by placing the suction fan 8 opposite the upper half of the pile of lumber with the heating pipes 9 covering the lower vertical half of the pile. The side walls of the chamber are thus curved so that air is drawn by suction through the upper half of the pile and circulated under pressure through the lower half of the pile.

In Figure 4 the structure of Figure 3 is further modified by putting a second suction fan on the opposite side of the pile adjacent the lower half of the pile, and a second set of heating pipes 9 above this second fan. A more rapid circulation is obtained by the dual arrangement.

The direction of travel of the drying gas in Figures l to 4, is horizontally through the pile, and then vertically along the curved walls to a dilerent horizontal passage.

In Figures 5 and 6 the air is again passed horizontally through the pile, but it is reversed in direction in the same horizontal plane. Vertically extending curved walls 12 and 13 are joined at apex 12 which is perpendicular to the line of the axis of suction fan 8. The kiln'is of greater length than height, so that while the diameter of the blower is the same as the height of the pile, the fan extends only across the middle two quarters of the length of the pile. Air is drawn by suction through the middle quarters and then directed by the curved walls in horizontal tlow, across heating pipes 9, and then through the end quarters, respectively, of the pile. Curved walls 13 and 14' then direct the air to the middle quarters, the horizontal ow being maintained. On the pressure side of this system, a conduit 10 having a throttle l11 communicates with the fan so as to form a steam out et.

Although the structure of Figures l to 6 shows a stationary pile of goods on carriage 3, such can be replaced by a conveyor belt for the continuous passage of material through the chamber. Again, a plurality of superimposed conveyor belts can be placed in the chamber, this lbeing especially suitable for drying sheets of veneer.

The advantages of the invention are in the simplicity of the construction of the chamber, and the eliciency of Patented Feb. 21, 1956,

operation`- due'to'tliefaet that' the chamber very closely encompassesthe-pilea oi lumber., No elaborate. conduit: systems are involved, and all of the drying action of the gaseous medium is directed to the material being dried rather than am extraneous structure.'

If., A kiln3 for dryingf materialsarranged a pile of horizontal'iayers vertically spaced" apart comprising: achamber' Having' all its inner' wallsf-elosely encompassing thefpilega sunt-ion' fanhaving'a' diameter equal to one= offthe'maior dimension of tlie''pilemounted' om one sidelwall of'said" chamber its Blades'yertiealiy extendTr ing; over the middletwo vquarters of tiie height4 of thepiier androtatalle inl aiplane Virrt close cl'araucev with` thei pile; arrst-curved` surface in; saidwali extending; from tle axis off said .fante atrend of said chamber for directing d'rying gas moved by1sadfanto-tlie partofthechamber notl coveredby' said fan: whereby thev drying gas will ow under: pressure throughY saidVv pile tetlie oppositeside wall, a; second curved' surface oppositelyfcing said first' surface; for directingthe drying gas 'without substantialv loss` ofk velocity totheportionoit?v said pilelyi'ng opposite saidL fanaandlthenfthrough said pile to said fan forrecircula'- y tion, and similar curved surfaces extending from the axis -osaidamto=rthez other endof-= saidl chamber.

2. A kiln as in claim l, further comprising a blower fan mounted on said opposite side wall, said blower fan having a size similar to said suction fan. I,

3. A kiln as in claim 2, further comprising said blower fan being mounted in axial alignment with said suction fan.

References Cited in the lerof thistpatent UNxTED STATES' PATENTS 965,251 Von Susslind' Ii1l`y 26'; 1910 1,326,161'. Alisopetal Maw" Dee: 3.0,'11919 1,547,891 Ayres 2... July 28, 1925 1,550,422 Brae'rner Aug. 8, 1927 l,648,468 Younger Nov. 8, 1927 2,050,597 Younger Aug. 11, 1936 Y FOREIGN winnersI 422,236 Great. Britain: f 'Iam 8,1, 1935 OTHER REFERENCES Proctor Laboratory'Drier, Bulletin #278i Proctor and Schwartz, Inez, Philadelphia, Pat, page'4i Italy -.s Apr. 191.19118Y 

1. A KILN FOR DYRING MATERIAL ARRANGED IN A PILE OF HORIZONTAL LAYERS VERTICALLY SPACED APART COMPRISING A CHAMBER HAVING ALL ITS INNER WALLS CLOSELY ENCOMPASSING THE PILE, A SUCTION FAN HAVING A DIAMETER EQUAL TO ONEHALF OF THE MAJOR DIMENSION OF THE PILE MOUNTED ON ONE SIDE WALL OF SAID CHAMBER WITH ITS BLADES VERTICALLY EXTENDING OVER THE MIDDLE TWO QUARTERS OF THE HEIGHT OF THE PILE AND ROTATABLE IN A PLANE IN CLOSE CLEARANCE WITH THE PILE, A FIRST CURVED SURFACE IN SAID WALL EXTENDING FROM THE AXIS OF SAID FAN TO AN END OF SAID CHAMBER FOR DIRECTING DRYING GAS MOVED BY SAID FAN TO THE PART OF THE CHAMBER NOT COVERED BY SAID FAN WHEREBY THE DRYING GAS WILL FLOW UNDER PRESSURE THROUGH SAID PILE TO THE OPPOSITE SIDE WALL, A SECOND CURVED SURFACE OPPOSITELY FACING SAID FIRST SURFACE FOR DIRECTING THE DRYING GAS WITHOUT SUBSTANTIAL LOSS OF VELOCITY TO THE PORTION OF SAID PILE LYING OPPOSITE SAID FAN AND THEN THROUGH SAID PILE TO SAID FAN FOR RECIRCULATION, AND SIMILAR CURVED SURFACES EXTENDING FROM THE AXIS OF SAID FAN TO THE OTHER END OF SAID CHAMBER. 